Humic acid is a kind of organic matter with the properties of favorable biological activity, adsorption, chelation and exchange ect, which has an important application and development potentiality in agricultural production. The humic acid matter and the like can improve soil physicochemical property and utilization efficiency of a fertilizer, stimulates crop growth, strengthen anti-adversity of crop, and improve quality of agricultural product. The mainly content of humic acid is fulvic acid with high quality and good solubility. Fulvic acid is most active, strongest drought resisting and anti-adversity in humic acid. Fulvic acid can inhibit the dormancy of plant, make plant absorb constantly various nutrients, and enhance the physiological function of plant, so that it can be achieved to grow rapidly, optimize quality, and increase production. It is applicable to development of green agriculture without toxicity, pollution and nuisance, which makes the produced grain, vegetable, amphisarca etc. meet with the requirement of the green food, and is in favor of ecological environment and human health. In the past 30 years, fulvic acid is occupied a predominance in fertilizer for spraying on leaf surface and drought resistance agent. But fulvic acid is expensive and limited resources. Ulmic acid and black rotten acid exist extensively in weathered coal, brown coal, peat and so on, and the cost is cheap. But it induces scarcity of resources due to the exploitation of a large amount of coal resource.
CN103275333A discloses like-humic acid extract from crop straw and a method for preparing a compound fertilizer thereof. The resource utilization ratio is optimized by extracting humic acid and fulvic acid in rice straw. And the environment pollution caused by rice straw is reduced indirectly. Meanwhile, the production environment of crops can be improved by utilizing the compound fertilizer made from the like humic acid extract. The compound fertilizer provides with more nutrition for the growth of crops, and enhances the anti-adversity of crops.
CN101040622A discloses a method for preparing a humic acid composite for adjusting plant growth by plant straw. The method comprises: crushing and mixing at least one of corn straw, jowar straw, wheat straw and rice straw, disinfecting at 80˜90° C. for 10˜30 min, then cooling to 35-40° C., adding quick effective bacterial to ferment for 10-20 days, and obtaining an extractive solution. The solution of the invention can be stored for long time at normal temperature. In the invention, the product prepared by plant stem such as corn straw, jowar straw, wheat straw and rice straw as materials, has health-care function on plant. The invention can improve yield with significant social and economic benefits.
The fulvic acid or the humic acid solution with a certain concentration of potassium, sodium, and ammonium salt is applied in the crop at different bearing stages by seed soaking, dip in root, and sprinkling and so on. All the treatments can promote the growth of the crops, and accelerate the growing development of the crops. Thus, the output and quality of the crops are improved. The stimulation of the humic acid can make seed germination 2 to 3 days in advance, and the crops have a high germination rate, whole and strong seeding. And the humic acid has a special function on root system. In view of that, the humic acid is called “root system fertilizer”. Besides the root, the humic acid also can promote the growth of the trophosome above the ground. It is noteworthy that the stimulation of the humic acid is especially important for the early growth stage of the crops. The humic acid contains phenol hydroxyl, quinonyl and the other active functional groups. Those functional groups promote the increase of enzymatic activity in plant, and increase the intensity of breath and photosynthesis, which is good for the synthesis of material, running, and accumulation.
It is shown in research that fulvic acid with lower molecular weight and higher content of active functional group is obviously higher promotion action than other humic acid with higher molecular weight. It may be that the action of humic acid on promoting the cell elongation is greater than the one on promoting the cell division, whereas, the action of fulvic acid on cell division is more obvious. In addition, humic acid contains phenol hydroxyl, carboxyl, alcohol hydroxyl reactive groups, ect. These active groups can interact with plant in different ways. And it is shown in research that the stimulating activity of humic acid is reduced by closing these groups, especially closing phenol hydroxyl. And saying is a lot about the action of functional groups. Schnitzer et al. consider that phenol hydroxyl plays a main role, not relevant to carboxyl according to the saying of closing groups.
Whereas, in prior art, the humic acid composition or fertilizer has lower stimulating activity on plants.
In view of that, the present invention is provided.